If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

It can be distinguished from S. millenii in that: (1) the main body of the premaxilla is higher, its length being slightly longer than its height; (2) the anterior margin of the premaxilla is vertical; (3) the maxillary process of the premaxilla is very lon; (4) the maxilla is separated from external naris; (5) maxillary fenestra is circular and relatively small; (6) the ascending process ofquadratojugal is remarkably longer than the jugal process; (7) the ratio of the dentary length/height is distinctly small; and (8) the pubic peduncle of ilium is longitudinally narrower than acetabulum and so on.